This review compared the effectiveness and common adverse events of medication classes used to treat seasonal allergic rhinitis (SAR) in adolescents and adults, in pregnant women, and in children. We sought to compare the following classes of drugs: oral and nasal antihistamines and decongestants; intranasal corticosteroids, mast cell stabilizers (cromolyn), and anticholinergics (ipratropium); oral leukotriene receptor antagonists (montelukast); and nasal saline.
We identified English-language studies using a peer-reviewed search strategy. The following databases were searched on July 18, 2012, with no date restrictions: MEDLINE® (PubMed® and Ovid), Embase® (Ovid), Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews, and DARE (Database of Abstracts of Reviews of Effects).
We consulted a Technical Expert Panel to identify the treatment comparisons most relevant to patients and providers. Subpopulations of interest were individuals with asthma or eye symptoms. Outcomes of interest were patient-reported symptom scores, quality of life, and adverse events. Inclusion was limited to studies that reported an outcome of interest and directly compared drugs of interest that were approved by the U.S. Food and Drug Administration (FDA). Two independent reviewers performed study selection and data abstraction. Disagreements were resolved by consensus or a third reviewer.
We identified 59 trials that addressed 13 of 22 treatment comparisons of interest for adolescents and adults, 0 of 17 comparisons of interest for pregnant women, and 1 of 21 comparisons of interest for children. Across all comparisons, 20 of 39 drugs FDA approved for the treatment of SAR were studied. For adolescents and adults with SAR, evidence was sufficient to form the following conclusions. For the treatment of nasal symptoms, montelukast (oral leukotriene receptor antagonist) and intranasal corticosteroid were similarly effective (high strength of evidence [SOE]). For the treatment of nasal symptoms and eye symptoms, intranasal corticosteroid, nasal antihistamine, and combination intranasal corticosteroid plus nasal antihistamine were similarly effective (high SOE), and montelukast and oral selective antihistamine were similarly effective (moderate SOE). For improved quality of life, montelukast and oral selective antihistamine were similarly effective (moderate SOE), and combination oral selective antihistamine plus intranasal corticosteroid was superior to oral selective antihistamine alone (low SOE). To avoid insomnia, oral selective antihistamine was superior to oral decongestant and to combination oral selective antihistamine plus oral decongestant (moderate SOE). In patients codiagnosed with SAR and asthma, montelukast was superior to oral selective antihistamine for reduced asthma rescue medication use (moderate SOE). In sensitivity analyses using a lower threshold for minimum clinical effectiveness, combination oral selective antihistamine plus oral decongestant was superior to oral selective antihistamine alone for the treatment of nasal symptoms in adolescents and adults with SAR (moderate SOE). In this population, we did not find evidence that any single treatment was both more effective and had lower risk of harms. Evidence for both effectiveness and harms was insufficient regarding the comparison between oral selective and oral nonselective antihistamine in children. All effectiveness and harms outcomes were limited by short trial durations.
Several effectiveness comparisons demonstrated similarity of treatments for selected outcomes. For most harms comparisons, the evidence was insufficient. Conclusions were limited by (1) lack of comparative evidence for all drugs within each class and (2) lack of evidence on the magnitude of symptom change that constitutes a minimal clinically important difference.